So I have a few 5TB external drives with all my media. I mainly just hook them up to my xbox and use kodi to play the files locally. I should probably be investing into a NAS or some sort of JBOD, but that's a whole other issue.

So no drive is backed up but they are all new (about 6 months old). Obviously, hdd drives can have mechanical failure, be a dud, or just plain suck. I do smart check and make sure the drive health is fine. I have been reading about bit rot and not sure if that is something I have to worry about and an immediate thing (or it's just some snake oil shit). I want to make sure the data stays readable and in best shape I can have it in for as long as possible. From the reading I have done surfin the web "refreshing" the data is usually done by rewriting the data. I guess what I am worried about is data corruption. With all this being on a HDD, mechanical failure is probably a bigger issue, and is something I should eventually get to with actual backups/parity. Drives are getting cheaper but I don't have the cash to drop right now on better/larger/enterprise (or NAS) drives to set all that up. I don't really want to re-download 20+ TB of stuff just to rewrite my data or shuffle data back and forth between my computer and the drive to rewrite. I could be going about this all wrong, so some pointer or input is helpful.

I use CrystalDiskInfo and HD Tune Pro to check drive health, but kinda just wanted to know if there are programs make help against data corruption, if it's even something that I should be immediately worried about, if I'm going about this in a dumb way, or if I should just start saving and work towards bulding a NAS, JBOD, ZFS or some shit. (if I'm honest all that shit seems out of my ballpark cause I like to just download and play, but it may be time to learn more about all that shit with regards to raid, parity, and having true backups)

tl;dr : I want to keep my shit for as long as possible on my HDDs. Back ups = good, but short of doing that, how to make sure data I currently have stays healthy on current drives?